我对楼主需求的理解是:
做A类业务的客户就是A类客户
做B类业务且不做A类业务的客户就是B类客户
做C类业务且不做A、B类业务的客户就是C类客户
做D类业务且不做A、B、C类业务的客户就是D类客户依照我的理解,实现的方式如下:select E.companyID
max(E.客户类型) as 客户类型
from
(select distinct companyID, 'A' as 客户类型 from A
union all
select distinct companyID, 'B' as 客户类型 from B
union all
select distinct companyID, 'C' as 客户类型 from C
union all
select distinct companyID, 'D' as 客户类型 from D) E
group by
E.companyID
做A类业务的客户就是A类客户
做B类业务且不做A类业务的客户就是B类客户
做C类业务且不做A、B类业务的客户就是C类客户
做D类业务且不做A、B、C类业务的客户就是D类客户依照我的理解,实现的方式如下:select E.companyID
max(E.客户类型) as 客户类型
from
(select distinct companyID, 'A' as 客户类型 from A
union all
select distinct companyID, 'B' as 客户类型 from B
union all
select distinct companyID, 'C' as 客户类型 from C
union all
select distinct companyID, 'D' as 客户类型 from D) E
group by
E.companyID
max(E.客户类型) as 客户类型
from
(select distinct companyID, 'A' as 客户类型 from A
union all
select distinct companyID, 'B' as 客户类型 from B
union all
select distinct companyID, 'C' as 客户类型 from C
union all
select distinct companyID, 'D' as 客户类型 from D) E
group by
E.companyID
max(t.客户类型) as 客户类型
from
(select distinct companyID, 'A' as 客户类型 from A
union
select distinct companyID, 'B' as 客户类型 from B
union
select distinct companyID, 'C' as 客户类型 from C
union
select distinct companyID, 'D' as 客户类型 from D) t
group by
t.companyID
(
select distinct companyID, 'A' as 客户类型 from A
union all
select distinct companyID, 'B' as 客户类型 from B
union all
select distinct companyID, 'B' as 客户类型 from C
union all
select distinct companyID, 'B' as 客户类型 from D
)a group by companyID
(
select distinct companyID, 'A' as 客户类型 from A
union all
select distinct companyID, 'B' as 客户类型 from B
union all
select distinct companyID, 'c' as 客户类型 from C
union all
select distinct companyID, 'd' as 客户类型 from D
) a
group by companyID在查询分析器中执行时把标点改为在英文状态下的